Ignition device



May 4, 1943 P MxEvss IGNITION DEVICE Filed May 29, 1940 .Q I I EN n mi. Im. C//I//w N o-m W m. Eu, wmf

Patented May 4, 1943 d UNITED STATES PATEN oFF-ICE IGNITIoN nevica Fred mese, Gary, rnd. Application May 29, 1940, serial No. 337,953

` 4 claims. (ci. 11s-11s) Figure 2 is a sectional .view taken on the lim whereby temporary failure of ignition of the i name win be immediately remedied. The moet common of these devices takes the form of a'. metallic fuel feed tube having at the inlet end thereof means for supplying gas and air in the desired proportions, together with electrodes at the exit end thereof to provide the spark adjacent' the flame area. Usually there is provided exteriorly of the fuel feed tube a porcelain insulator extending longitudinally thereof ``and supporting an electrode -which extends co-incident therewith.

This electrode terminates adjacent the end of the metallic fuel feedtube which is groundedand therefore provides the necessary spark gap therebetween. Such construction is diflicult to suitably operate over substantial periods `of time for the reason that the porcelain insulator extends with the fuel feed tube into the furnace and thus gets very hot while the other end of the porcelain is relatively cool. This difference in temperature results in the breaking of the porcelain tube at the point where it enters the furnace, which is through a, metallic plate; thus there results-the grounding of the spark at this Vpoint instead of at the point where the fuel issues from the fuel feed tube. In addition the yelectrodevextending 'coincident to the porcelain insulator. is also at a high temperaturedue to exposure to the heat of the furnace and `thus deteriorates rapidly.

Further-the distance fromwhich, the Awire issupported from the porcelain electrode makes it ex- Figure 3 is an exit or outlet end view of the fuel feed tube of Figures 1 and 2.j

Referring more particularly tothe drawing the numeral 2 designates a metallic fuel feed tube having the usual inlet end `2a. and outlet end 2b, the latter of which is adapted'to extend within the furnace with which the device of the invention is to operate. At the inlet end 2a of the fuel feed tube 2 there is provided the usual means 3 for supplying gas togetherjwith an air inlet 4.

In the side wall of the fuel feed tube 2 there is a screw-threaded aperture 5 which is adapted to receive the externally screwthreaded housing 6 of a conventional spark plug from which the ground electrode has been removed. Within the spark plug housing 8 there is disposed in screwa threaded engagement therewith the spark plug sleeve 1 which is adapted to hold in rigid relationship therein the porcelain insulator 8 of the spark plug, the center electrode 9 extending therethrough and well into the center of the fuel feed tube 2.- The extended end of the center electrode 9 is screw-threaded and carries thereon an internally screw-threaded sleeve I0 which 'has a cross-aperture I2 therein.V This crossaperture I2 receives an elongated electrode I3 which projects from the exit end 2b of the fuel feed tube 2..- The exitv end 2b of the fuel feed tube 2 is provided with 'a refractory cap I4 having a series of apertures I5 therein, one of which f. vwith a ground electrode I'I similar to that of av oeedingly diicult to maintain an accurate adjustment of the sparkgap. Moreover the spark from the-electrode to the grounded end of the fuel feed tube is disposed in offset relationship with respect to the path of the issuing fuel and therefore does not always give prompt ignition.

It is among the objects of the present invention to eliminate the foregoing difficulties and Y Provide devices of the class described which are easy .and inexpensive to manufacture and maintain.

The foregoing and other objectswill be more apparent after referring to the drawing, in which: j

Y Figure 1 is a top plan view of a fuel feed tube embodying my Invention;

is centrally disposed to receive and have protruding therefrom, the extended end of the electrode I3. Thisr'efractory'cap I4 is suitably retained in the end of the fuel feed tube 2 by means of a screw-threaded retainer cap I6 which is provided conventional spark plug.

` Immediately opposite the screw-threaded aperture 5 in the fuel feed tube 2 is a similar aperture I9 in which there is disposed a screw-threaded plug 20. By removing the screw-threaded plug 20 and loosening the externally-threaded sleeve 'I of the spark plug the porcelain insulator l may be rotated to relieve the set-screw effect of the electrode 9 with respect to the electrode I3 whereby the latter may be suitably'adjusted, After the desired adjustment the porcelain insulator 8 may be rotated to again obtain the setscrew effect of the electrode! with respect to the electrode I 3 and the externally-threaded sleeve 'I drawn tight to maintain the adjustment. From the foregoing it will be seen that there is provided a spark gap directly in the path of the fuel stream whereby the electrical or voltage stress on the porcelain' insulator 8 is practically eliminated Vwhen the fuel is ignited when the flame is, a sufficiently good electrical conductor to form what practically amounts to a short without the furnace and therefore ,is not-sub ject to the deteriorating effect of heat. Due to the provision of the aperturev cap I4 the central aperture of which receives and may be made to rigidly hold the electrode I3 an accurate adjustment of the spark gap may be maintained.

While I have shown and described one specific embodiment of my invention, it will be understood that I do not wish to be limited exactly thereto since various modications may be made within the scope of my invention, as defined `by the following claims.

I claim: i i

1. The combination with a tubular'fuel burner of an electrode disposed therein and extending longitudinally thereof, said electrode terminating adjacent the discharge end of said tubular fuel burner, means for supporting the outer end of said electrode,` a grounded electrode disposed ad- Jac' it the outer end ofjsaid'iirst-named electrode andfdetlning a 'spark gap therebetween, said spark gap Abeing in the path ofthe main fuel stream. an electrical x conductor extending through the side wall of said tubular fuel burner,

and a supporting element slidably mounted on.

said first-named electrode, the inner end of said electrical conductor being adaptedto coact with said supporting element asa set-screw for securing said first-named electrode against longi-v tudinal displacement. Y

2.' The combination with a tubularfuel burner of an electrode disposed therein and extending axially thereof, said electrode terminating adjacent the discharge end of said tubular fuel burner, means for supportingthev outer end of said electrode, a grounded electrode disposed adas a set-screw for securing said rst-namedelectrode against longitudinal displacement.

3. The combination with a tubular fuel burner of an electrode disposed ,therein and extending longitudinally thereof, said electrode terminating adjacent the discharge end of said tubular fuel burner,` means for supporting the outer end of said electrode, a grounded electrode disposed adjacent the discharge end of said burner and the outer end of said mst-mentioned electrode and vdefining a spark gap therebetween, said spark gap disposed directly in the path of the main fuel stream of the burner whereby the electrodes are cooled by said main fuel stream as it issues forth from said burner, thereby eliminating overheating of said electrodes and the spark gap between the electrodes being short circuited by the flame as soon as the fuel ignites jacent-the outer end of said rst-named electrode and deilning a spark gap therebetween, said spark gap being in the path of the main fuel stream. an electrical conductor extending at a substantial right-angle through the side wall of said tubular fuel burner, and a supporting element slidably mounted on said first-named electrode, the inner end of said electrical conductor being adapted to coact with said supporting element so that the potential diiference between the electrodes is removed thereby eliminating electrical stress from the electrical insulation, an electri- -cal conductor extending into said tubular fuel burner intermediate the length thereof, and means carried by said conductor within said burner for supporting the inner end of said firstmentioned electrode.

4. The combination with a tubular fuel burner of an electrode disposed therein and extending longitudinally thereof, said electrode terminating adjacent the discharge end of said tubular fuel burner. means for supporting the outer end of said'electrode, a'grounded electrode disposed adjacent the discharge end of said burner and the outer end of said first-mentioned electrode and dening a spark gap therebetween, said spark gap disposed directly in the path of the main fuel stream whereby the electrodes are cooled by the main fuel stream as it issues forth from said burner thereby eliminating overheating of said electrodes, and the spark gap between the elecv trodes being short circuited by the flame as soon as the fuel ignites so that the potential difierence between the electrodes is removed thereby eliminating the electrical stress from the electrical insulation, an electrical conductor extending into said tubular fuel burner intermediate the length thereof, means carried by said electrode within said burner for supporting the inner end of said first-mentioned electrode and adjustable means arranged with said last-mentioned means whereby said first-mentioned electrode can be moved and adjusted longitudinally of said fuel burner.

FRED m8. 

